Decrease in protein binding and its effect on toxicokinetics (TK)/toxicodynamics (TD) of diclofenac and propranolol in pregnant rats.

Article Details

Citation

Miida H, Noritake Y, Shimoda H, Honda K, Matsuoka T, Sakurai K, Shirai M, Manabe S, Takasaki W, Ueno K

Decrease in protein binding and its effect on toxicokinetics (TK)/toxicodynamics (TD) of diclofenac and propranolol in pregnant rats.

J Toxicol Sci. 2008 Dec;33(5):525-36.

PubMed ID
19043274 [ View in PubMed
]
Abstract

Plasma protein binding is an important factor for the kinetics of drugs and how they act since it is the first step in drug distribution. Physiological changes in pregnancy, which include plasma composition, can affect drug binding and subsequent drug response. In the present study, we investigated the toxicokinetics (TK) and/or toxicodynamics (TD) of diclofenac and propranolol comparing pregnant Sparague-Dawley (SD) rats with non-pregnant SD rats in terms of protein binding and drug distribution. Diclofenac and propranolol are reported to bind to albumin and alpha(1)-acid glycoprotein (AGP), respectively. After a single administration of diclofenac, the area under plasma concentration-time curve (AUC) based on free diclofenac in pregnant rats was 3.9 times higher than that in non-pregnant rats. This difference is considered to be due to a lower concentration of serum albumin and a higher concentration of non-esterified fatty acid (NEFA) that inhibits drug binding to albumin, in pregnant rats. In histopathological examination, more severe gastrointestinal toxicity was observed in pregnant rats at 24 hr after dosing. This severe toxicity was likely to be correlated with the higher AUC. With respect to propranolol, the difference of the AUC based on free propranolol was not clear although the concentration of serum AGP was lower in pregnant rats. However, the binding analysis data suggested a difference of protein binding at a lower propranolol concentration range. Consequently, lowered serum proteins and increased NEFA in pregnant rats can lead to low protein binding, subsequent increase in free drug concentrations, and eventual increase in the TD of drugs.

DrugBank Data that Cites this Article

Drug Carriers
DrugCarrierKindOrganismPharmacological ActionActions
PropranololAlpha-1-acid glycoprotein 1ProteinHumans
No
Not AvailableDetails
PropranololSerum albuminProteinHumans
Unknown
Not AvailableDetails